Temperature control for folding machines, etc.



1927; Apr! o. E. cooK TEMPERATURE CONTROL FOR FOLDING MACHINES ETC Filed k, r M w u 7 i m m w A W 3 3 4. L \z M 1% Z W m W 3 w .v a w L U M Patented Apr. 26, 1927.

UNITED STATES PATENT OFFICE.

ORVILLIJ COOK, F TROY, YORK, ASSIGNOR- TO CLUETT, PEABOD'Y (30., IND OF TROY, NEW YORK, .A CORPORATION OF NEW YORK.

TEMPERATURE CONTROL FOR FOLDING MACHINES, ETC.

Application filed November 14, 1925.

In many thermostatically controlled devices and appliances trouble results from momentary opening or closing of the thermostat when the temperature is near the upper and lower limits oi? the thermostat. For example, in a tolding machine for folding and pressing collar blanks in the manufacture oi collars which has a thermostat in the heated bed for regulating the temperature oil the bed, vibration of the machine causes this momentary opening and closing, there by causing the heating circuit to be opened and closed so often that the contact points are soon destroyed by arcing.

Objects of the present invention are to avoid the unnecessary actuation of the circuit closer (or other thermostatically controlled device) due to momentary opening or closing of the thermostat as a result of jar or other cause when the thermostat is at a temperature near its opening or closing temperature and to provide means to this end which are simple and reliable in operatlon.

The genus of the invention is set forth in the accompanying claims and illustrated by one concrete embodiment in the accompanying drawings in which- Fig. 1 is a diagram showing normal operative positions;

Fig. 2 is a diagram showing the positions resulting from opening of the thermostat;

Fig. 3 is a diagram showing the parts in open or inoperative positions;

Fig. 4: is a diagram showing the parts in the positions which they occupy when the thermostat closes momentarily; and

Fig. 5 is a side view of one form of slowacting heat-controlled switch applicable to the present invention.

In the particular embodiment illustrated in the figures, H represents a heating element which may for example be the resistance heater in the bed plate of a folding machine; 12 the main circuit for the heater which may be connected to a suitable source of current through switch X; A a circuit closer for the heater circuit which is opened by a spring and closed by the magnet R in the energizing circuit 3-4-5-6; M a switch in the energizing circuit; '1 a thermostat associated with the heater H, the thermostat having a cold position 0 in which it engages a contact 7 and a hot position it the parts in the parts in momentary Serial No. 69,002.

in which it is separated from the contact 7, P the primary of a transformer in series with the thermostat T in a circuit 8-910 which is in parallel with the heater circuit l-2, and S the secondary of the trans former which is connected in series with a heat-responsive element in the circuit 511. In parallel with the switch M is a locking circuit comprising conductors 12 and 15 and switch N.

The two switches M and N are intercom nected as illustrated in Fig. 5. The switch N comprises a flexible leaf contact member lat iixcdly mounted on a suitable support and insulated from the flexible contact element 15 by insulation 16. The element 15 may be formed of phosphorus bronze and has a depending arm 17 hooking under the element 18 of switch M. Element 18 is preterably rigid and pivotally mounted on a suitable support at 19. The arm 18 is insulated from the arm 17 by insulation 20 riveted to arm 18. A stationary contact 21 is fixedly mounted in the path of arm 18 so that the circuit is closed between 18 and 21 when the arm 18 is swung in a counterclockwise direction about the pivot 19.

In the particular embodiment illustrated in the drawings the switches M and N are actuated by a wire W which is formed of some material such as nichrome resistance wire having a relatively high coefiicient of expansion. This wire is attached to the arm 18 at its upper end and at its lower end to an adjusting screw 2 which threads up and down in a fixed support 23. The wire W is so adjusted by means of screw 22 that both switches are held in open position when the wire is cold and so that the switches may both close when the wire is heated by current derived from the transformer secondary S through the circuit 5-11. The spring element 15 is resilient and so mounted that it not only tends to spring into engagement with contact 1a but is strong enough to lift arm 18 into contact with 21 when the wire is heated.

l Vhen the thermostat T is closed (Fig. 1) heating current flows through the circuit H1A2; current also flows through 87T9P--10 to induce current in circuit S5VV-11 thereby heating wire TV sufiiciently to permit the switches M and N to close; energizing current is supplied to magnet B through the circuit 3Ri CJI Lil

.\l5(i; and the magnet R is locked independently of switch M by the circuit 3R-" -12N1 31A-2.

When the thermostat T is opened momentarily, (Fig. thereby momentarily stopping the heating current in W', the wire i starts to contract, first opening switches M. However this does not tie-energize magnet- R llitiSlilUCli as it is locked by the aforesaid locking circuit; only prolonged opening of the thermostat will cause the switch M to open. After the thermostat T has been open some time the wire \V contrtcts suitito open the svit-ch N, thereby demagnet R which permits arma- -:i open the heating circuit. The are then in the position shown in v 'ill oi course be unoerstood that the tion or the thermostat lags somewhat beid ile heatii and cooling oi; the lcatei',

mvinn to the time required for transmission of heathen. the heater to the thermostat. Consequently the thermostat continues to ve away from the contact T for a time or the circuit Q-91O is broken the slow :1: ion of the wire VF also contributing to this conlinucd opening of the therrostat. However utter the heating circuit has been open for a period the thermostat sta to close and it approaches the contact T it may make momentary contact several times before it preses against the contact with suiiicient force to remain ciosed. Each of these momen ary contacts causes the wire W to be momentarily heated but by properly predetermining; the spaces between the contacts oi the two switches. the space between the contacts of switch N being less than the space between the contacts of switch M, and also by adjustn'ient of the amount of heating current flowing through wire V? and the rate oi expansion of the wire Ti this momcntary closing does not cause the wi e ii to expand sui'liciently to close the switch M. iVhile the switch I? may be closed by this momentary closing of the thermostat the switch X does not energize mag-net R but only serves to mz'iintain the magnet energized after its circuit is first closed by switch M.

In applying this invention to folding machines the temperature of the bed plate of the folding machine may be maintained within a narrow range by an ordinary thermostat which may chatter considerably when it is about to open or close. For example the temperature may be readily maintained between the limits or" 4410" and 460 in which case the parts may be adjusted so that th thermostat may start to open at approximately 457 and start to close at approx? mately 443, it being understood that the aforesaid lag will result in the temperature of the bed plate rising a few degrees after the thermostat has opened and continuing to fall a tow degrees even utter the thermostat is again closed. Thus this invention greatly reduces the number of times the circuit is opened and closed by the i'nagncc l3 thereby greatly prolonging the life of the contacts of the a mature A.

I claim:

1. Apparatus for controlling an electric heater comprising a circuit closer for connection in circuit with the heater, a magnet for actuating said circuit closer, at thermostat responsive to said heater for controling the closer,

noinentary opening and closing of said thermostat i i-om aii'ecting said magnet.

2. Apparatus for controlling an electric heater coi'i'iprising a cirzisit closer for conneclion in circuit with the heater, a magnet for z'ictnating said circuit L'lOf-Di, a iherinostat responsive to said heater; :1 switch tor and means for preventing an electric means irresponsive to momentary opening or closing of the therinost at but rcspi'nisive mostat for 21K cine said switch.

3 irppartt for con "llinp; an electric 1 :ection in circiit with the heater, a magnet for actuatin sai'l circuit closer, a thermoto saic of by said thermwat for energizing the iagnet a locking circuit for the magnet, nd slo V 'i "he thermosta but responsive t0 pioiongcd opening of the thel C Apparatus for cinnr n heater comprisin yr, a nr net "for actuating sa'd c'rcut a il1(lii1(i li\ i t trolled by said thermostat tor encrgz'izinethe magnet, a locking circuit for the magnet,

thermostatior "rst closing the locking circuit and later closing the energizing circuit.

the type which generates heat when a circuit is closed comprising a circuit closer in said circuit closer. a thermostat responsive to said stat tor energizing" the magnet, a locking: cir

. a switch in each of said controlliiu; the circuit oi? said closer, and

to prolonged opening or closing of "he thereater comp ising a circuit closer for conresoonsiyc i heater, a circuit cony-zi, 1r,"- mca s irrespensive to 'iomc-zni'ary openn oi i in l: circuit.

1 necti n in circuit with the 7/ i l I stat responsive to said I i: a circuit conand slow-acting; means responsive to the 5. Apparatus for controlling a heater ol 1 ircuit, a magnet for actuating; said heater, a circuit controlled by said thermocuit for the niagne energizing and locking circuits, and means respo sive to the thermostat tor actuating the two switches in sequence. the locking no closed and oncned respectively L to momentary closure and proc i opening ot' the theren'iostat and the energizing switch being closed and opened respectively in response to prolonged closing and momentary opening of the thermostat whereby the heater circuit unaffected by momentary closing or opening of the thermostat.

6. Apparatus for (10lltl0lling an electric heater comprising a circuit closer in circuit with the heater, slow-acting temperature-- controlled means for controlling the circuit closer, and a thermostat responsive to the heater for controlling said means.

7. Apparatus for controlling a heater comprising a control circuit a circuit closer in said circuit, slow-acting temperature-controlled means for controlling the circuit closer, and a branch circuit containing a thermostat responsive to said heater, and means for supplying heat to said slow-acting means when the thermostat is closed.

8. Apparatus for controlling a heater comprising a control circuit a circuit closer in said circuit, a magnet for actuating said circuit, a thermostat responsive to said heater tor controlling the closer, and means con trolled by the thermostat for controlling the magnet, said means being irresponsive to momentary opening and closing of the thermostat.

9. Apparatus for controlling a heater comprising a control circuit a circuit closer in said circuit, a thermostat responsive to said heater, and a delayed-action switch irresponsive to momentary opening and closing of the thermostat but responsive to prolonged opening or closing of said thermostat for controlling said closer.

10. Apparatus for controlling a heater comprising a control circuit a circuit closer in said circuit, a thermostat responsive to said heater for controlling the closer, a switch interposed in said circuit for pre venting momentary opening and closing of said thermostat from affecting the magnet, and means responsive to prolonged opening or closing of the thermostat for controlling said switch.

11. Apparatus for controlling a heater comprising a control circuit a circuit closer in said circuit, a magnet for actuating said circuit closer, thermostat responsive to said heater for controlling the closer, locking circuit comprising a movable arm interposed in said circuit for preventing momentary opening and closing of the thermostat from atiecting the magnet, and means responsiveto prolonged closing oi the thermostat .i'or controlling the movable arm.

12. Apparatus for controlling heater comprising a control circuita circuit closer in said circuit, a magnet for actuating the closer, an enegising circuit in parallel with the heater control circuit and containing said magnet, an energizing switch in said energizing circuit, a locking circuit in parallel with said switch and with said heater control circuit, a locking switch in said locking circuit, a thermostat responsive to said heater, and slow-acting means controlled by said thermostat for actuating said switches in scquence, the locking switch being closed only in response to prolonged closingoi? the thermostat.

13. Apparatus for controlling an electric heater comprising a control circuit including said heater a circuit closer in said circuit, a magnet for actuating the closer, an energizing circuit in parallel with the heater and containing .aid magnet, an energizing switch in said energizing circuit, a locking circuit in parallel with said switch and with said heater, a locking switch in said locking circuit, a thermostat resnonsive to said heater, and slow-acting heat responsive means controlled by said thermostat for actuating said switches in sequence, the lOCling switch being opened only in response to prolonged opening of the thermostat.

Signed by me at Troy, New York, this 11 day of November, 1925.

ORVILLE E. COOK. 

